Objective To investigate the effects of low dose radiation on the level of oxidative damage and antioxidant in population of high background radiation area of Guangdong.Methods A total of 48 male residents who lived in high background radiation area(HBRA) of Guangdong province and 48 male residents who lived in neighboring Enping control area were chosen as the objectives and control respectively.The peripheral venous blood of two groups was collected,and then the levels of 8-OHdG and TrxR were determined by enzyme linked immunosorbent assay (ELISA).Results Compared with the CA group [(315.39 ± 100.59) ng/ml],the level of 8-OHdG [(272.64 ± 96.85) ng/ml] decreased significantly in HBRA (t =2.121,P ＜0.05).Compared with the CA group [(0.467 ±0.056) ng/ml],the level of TrxR [(0.496 ± 0.044) ng/ml] increased significantly in HBRA (t =-2.823,P ＜ 0.05).The results of multiple linear regression analysis demonstrated that the chronic exposure to low dose of radiation had significant effects on the expression level of 8-OHdG and TrxR (t =-2.327,2.367,P ＜ 0.05) after adjustment for confounding factors such as age,drinking,tea drinking,smoking,medical exposure and stressful events.Conclusions Chronic exposure to low dose radiation may decrease the level of oxidative and enhance the level of antioxidant.

The incidence of occupational injury accidents in the metallurgy and mechanical manufacturing industries remains high, posing risks not only to the safety and health of workers but also causing heavy economic burdens to enterprises and families. The occupational injury accidents in metallurgy and mechanical manufacturing industries were caused by the following six items： human factors, machine factors, building factors, raw material factors, environmental factors, and management factors. The types and body parts of occupational injury accidents varied among different industries due to the nature of the occupation and working environment. Occupational injury accidents were both sudden and preventable. Currently, comprehensive intervention measures for occupational injury accidents at China and abroad included safety education, improving work environments, optimizing building layout and facilities, and enhancing safety management capabilities. Effective and feasible intervention measures for occupational injury accidents should be based on the characteristics and causes of occupational injury accidents in each industry, and should include corresponding interventions for workers, machines, buildings, raw materials, environment, and management.

OBJECTIVE: To investigate the current status and influencing factors of occupational stress in female workers of labor-intensive enterprises. METHODS: Totally 910 female workers from 5 labor-intensive enterprises in Guangdong Province was selected as the research subjects by random cluster sampling method. A questionnaire survey on occupational stress was conducted using the Occupational Stress Inventory-Revised Edition. RESULTS: Among the 910 female workers,14. 9%( 136/910) showed medium or higher scale on occupational role level,20. 1%( 183/910) showed medium or higher scale on occupational stress level,and 21. 4%( 195/910) showed medium or higher scale on personal resources lack. Multivariate logistic regression analysis indicated that the risk of occupational stress was high in single female workers and/or those exposed to occupational hazards( P < 0. 01). The higher the occupational role level,the higher risk of occupational stress( P < 0. 01). The less personal resources,the higher risk of occupational stress( P < 0. 01).CONCLUSION: Some female workers in labor-intensive enterprises showed medium or higher occupational stress level. The main influencing factors of occupational stress are marital status,exposure to occupational hazards,occupational role and personal resources.

Objective To analyze and set up the effective dose of different ionizing radiation for tunnel construction workers. Methods A total of five tunnels constructed using drilling and blasting methods were selected as the research subjects using the convenient sampling method. The workplace γ radiation effective dose, radon concentrations, and radioactive activity concentrations were detected, and on-site surveys were conducted to estimate the internal and external irradiation doses and total effective doses for workers in different work sites. Results Radiological hazards in tunnels constructed using drilling and blasting methods included radon and its progeny, γ radiation, radioactive dust (uranium-238, radium-226, thorium-232, and potassium-40) and others. The average total effective dose of ionizing radiation exposure for tunnel construction workers was (6.730 1±1.541 1) mSv. The average dose of radon and its progeny was (6.163 0±1.512 8) mSv, radioactive dust was (0.014 6±0.009 1) mSv, γ radiation was (0.552 6±0.138 7) mSv. The dose of radioactive dust of radon and its progeny was 0.24%. Radon and its progeny contributed more to the radioactive dose than radioactive dust and γ radiation (all P<0.05). Among all the radioactive dusts, the dose contribution ranked from highest to lowest was thorium-232, uranium-238, and radium-226. Conclusion For tunnel construction workers, the largest contribution to the effective dose of ionizing radiation exposure is from radon and its progeny for internal irradiation, followed by γ radiation for external irradiation. The contribution of radioactive dust to internal irradiation dose can be considered negligible.

Noise is a common occupational hazard in workplaces. Long-term exposure to high-intensity noise mainly causes occupational noise-induced hearing loss (ONIHL). The development of ONIHL is irreversible, and there is currently no cure. At present, risk assessment methods based on noise exposure intensities mainly include risk index assessment method, Engineering Professional Council assessment method in United Kingdom (EDC assessment method in UK), National Institute of Occupational Safety and Health assessment method in United State (NIOSH assessment method in US), and International Standardization Organization assessment method (ISO assessment method). However, the risk index assessment method is subjective and does not consider the effectiveness of workers wearing protective equipment. The EDC assessment method in UK defines ONIHL differently from China. The NIOSH assessment method in US and ISO assessment methods have population data sources that deviate from China, which can lead to bias in risk assessment. In the future, it is necessary to further carry out application research on the risk assessment of ONIHL in Chinese noise-exposed workers, compare the applicabilities of various assessment methods, conduct large-sample population epidemiological studies for verification, and fully utilize the risk-prediction function to prevent and control ONIHL.

ObjectiveTo explore the protective effect of hearing protectors worn by noise-exposed workers and its influencing factors. Methods A total of 329 occupational noise-exposed workers were selected as the research subjects by judgment sampling method. A questionnaire survey on the use of ear protectors and individual suitability tests was conducted. Intervention was carried out for those whose personal attenuation rating (PAR) did not pass the baseline standard. Results The median (M) and the 25th and 75th percentiles of baseline PAR were 17.0 (5.0, 22.5) dB. The baseline PAR of the workers who were male, aged 25-<35 years, with a working experience of 5-<15 years, with a college degree or above, wearing ear protectors for 5-<15 years, knowing the right way to wear ear protectors, and workers who wore ear protectors correctly during work was relatively high (all P<0.01). The unqualified rate of baseline PAR of the study subjects was 32.8%. The unqualified rate of baseline PAR of workers in automobile manufacturing enterprises was lower than that of workers in plastic enterprises and textile enterprises (9.2% vs 43.6%, and 9.2% vs 50.0%, both P<0.01). The M of the 108 unqualified worker on baseline PAR was improved after intervention (22.0 vs 1.0 dB, P<0.01). The rates of knowing the right way to wear ear protectors, wearing ear protectors correctly during work, and receiving training on wearing ear protectors correctly for the research subjects were 88.1%, 84.8%, and 86.6%, respectively. Workers in automobile manufacturing enterprises and plastic enterprises had higher rates of knowing the right way to wear ear protectors, wearing ear protectors correctly during work, and receiving training on wearing ear protectors correctly than those in textile enterprises (all P<0.01). Conclusion Gender, age, working experience, education level, duration of wearing ear protectors, knowledge and use of ear protectors correctly are influencing factors of the protective effect of ear protectors for noise-exposed workers.

OBJECTIVE: To explore the changes of the serum immune cytokines in medical radiation workers exposure to low dose ionizing radiation. METHODS: Totally 244 medical professionals working with radiation(61 diagnosis radiology,51 nuclear medicine,74 radio therapeutics and 58 interventional radiology) from 7 hospitals of Guangdong Province were selected as study subjects by using the typical sampling method; 51 administration workers who did not expose to radiation were selected as control group. The radiation dose of these individuals was monitored by thermoluminescent measurement instrument for one year. Venous blood was collected and the levels of interferon γ(IFN-γ),interleukin 10(IL-10),transforming growth factor-β1(TGF-β1) in serum were examined by enzyme-linked immuno sorbent assay. RESULTS: The maximum annual average dose of radiation per person of the medical radiation workers was 0. 41 mSv/a. It was smaller than the occupational exposure limit(20. 00 mSv/a). The annual average dose of radiation per person in the group of nuclear medicine was significantly higher than those of diagnosis radiology,radio therapeutics and interventional radiology(P <0. 01). Among the male staffs,the expression of IL-10 in the diagnosis radiology group,radio therapeutics group and interventional radiology group was lower than that in the control group(P < 0. 05); the expression of IL-10 in radio therapeutics group was lower than those in nuclear medicine group and interventional radiology group(P < 0. 05); the ratio of IFN-γ/IL-10 in radio therapeutics group was higher than those in diagnosis radiology group,nuclear medicine group,interventional radiology group and control group(P < 0. 05). These individuals were divided into 3 different dose group(0. 03-,0. 06-and > 0. 15 m Sv/a) based on their average radiation dose. The expression of IL-10 in male staffs of these3 dose groups was lower than that of the male control group(P < 0. 05). CONCLUSION: Long-term low dose ionizing radiation may restrain the expression level of IL-10 in the male staffs.

Background: Classical swine fever virus (CSFV), the causative agent of classical swine fever (CFS), is a highly contagious disease that poses a serious threat to Chinese pig populations. Objectives: Many provinces of China, such as Shandong, Henan, Hebei, Heilongjiang, and Liaoning provinces, have reported epidemics of CSFV, while the references to the epidemic of CSFV in Yunnan province are rare. This study examined the epidemic characteristics of the CSFV in Yunnan province. Methods: In this study, 326 tissue samples were collected from different regions in Yunnan province from 2015 to 2021. A reverse transcription-polymerase chain reaction (RT-PCR), sequences analysis, and phylogenetic analysis were performed for the pathogenic detection and analysis of these 326 clinical specimens. Results: Approximately 3.37% (11/326) of specimens tested positive for the CSFV by RTPCR, which is lower than that of other regions of China. Sequence analysis of the partial E2 sequences of eleven CSFV strains showed that they shared 89.0–100.0% nucleotide (nt) and 95.0–100.0% amino acid (aa) homology, respectively. Phylogenetic analysis showed that these novel isolates belonged to the subgenotypes 2.1c and 2.1d, with subgenotype 2.1c being predominant. Conclusions The CSFV was sporadic in China’s Yunnan province from 2015 to 2021. Both 2.1c and 2.1d subgenotypes were found in this region, but 2.1c was dominant.

OBJECTIVE: To compare the applicability of two risk assessment methods to assess the occupational health risk of key industries of dichloromethane in Shenzhen City. METHODS: The Singapore ministry of manpower risk(MOM) method and the comprehensive index method were used to evaluate the risk of 123 positions in 47 key industries of dichloromethane in Shenzhen City. Then the risk classification results of the two assessment methods were compared. RESULTS: The results of MOM method showed that the median and the 0 th to 100 th percentile [M(P_0-P_(100))] of risk of dichloromethane in electronics industry was 2(2-3), and the risk level was low to medium. The M(P_0-P_(100)) of risk of dichloromethane in printing industry was 2(2-4), and the risk level was low to high. The results of the comprehensive index method showed that the M(P_0-P_(100)) of risk of dichloromethane in electronics industry and printing industry were 3(3-4), and the risk level was medium to high. There was no significant difference in the assessment results of occupational health risk of dichloromethane between the electronic industry and the printing industry by MOM evaluation method(P>0.05). The occupational health risk assessment of dichloromethane in printing industry was higher than that in electronic industry by the comprehensive index method(P<0.01). Both evaluation methods were not consistent in the electronics industry and the printing industry(k values were-0.01 and 0.04, all P>0.05). After merging the evaluation results of the two industries, there was no consistency in the evaluation results of the two evaluation methods(k value=0.01, P>0.05). CONCLUSION: The risk level of dichloromethane in printing industry is higher than that in printing industry in Shenzhen City. The comprehensive index method may comprehensively and objectively assess the occupational health risk level of dichloromethane in key industries in Shenzhen City.

ObjectiveTo analyze the results of fit testing and its influencing factors on half-mask respirator among workers exposed to organic solvents. Methods A total of 84 workers exposed to organic solvents were selected as the research subjects using a convenience sampling method. The qualitative fit test apparatus of respiratory protection was tested after the workers had put on the half-mask respirats, and 11 facial indicators of the subjects were measured. Results The overall pass rate of the respirator fit testing was 71.4% (60/84). The lowest pass rate was 63.1% (53/84), which occurred during bending movements of workers. The head width, minimum forehead width, face length, nose length, nose depth, head circumference and head length were higher in workers who passed respirator fit testing, compared with those in the failing group (all P<0.05). The result of binary logistic regression analysis showed that gender and face width were influencing factors of the respirator fit testing (both P<0.05). Female workers had a lower pass rate of the fit testing than male workers, and workers with larger face width had a lower pass rate in the fit testing. Conclusion Drastic movement may lead to a decrease in the seal of half-mask respirator of workers exposed to organic solvents. When providing half-mask respirator to workers exposed to organic solvents, employers need to pay attention to the fit of respirators of female works and those with larger face width to ensure the effectiveness of respiratory protection for workers.